A Characteristic Study Of Light-Induced Optical-Lattices As Waveguide

This paper have studied the guidance characteristic of the optical lattice waveguide to coherent beam evolving in it. Because of the good modulability of the light-induced optical lattice in the photorefractive materials, it has attracted a lot of interesting of researchers to use it to form waveguides, and the low-power, high non-linear rate make it a popular studied object in this field. By changing the beam energy distribution which is used to form the light-induced optical lattice, we can get a variety of waveguide shapes meeting the test requirements, and that give us a big convenience to study the waveguide.When the optical lattice parameters (depth, period) and the applied voltage match the signal energy, the beam will form a discrete solitons or the beam will show discrete diffraction if the beam energy is too low when transmitting in the optical lattice. If the lattice depth is too low to make any impact to the beam's transmission, the beam will perform as in the bulk material. The beam transmitting in one-dimensional lattice array waveguide will be well localized in the horizontal direction due to the local effect of the optical lattice, while in the vertical direction, the lattice seems has no effect on the beam's transmission as lattice's parameters are not changing with the direction. However the beam shows more stability in it. In addition, the beam's energy will be shifting along the lattice array as the array turns, and it will be guided completely by the lattice which has a small angle, thus the array plays an good role of waveguide. As the angle increases, the signal light will be divided into two parts under the effect of the lattice, one is transmitting in the lattice array and the other is not. and the proportion of the two parts shows different as initial energy of the signal light is different. When the beam transmits in two-dimensional micro-optical-lattice waveguide , in addition to the characteristics of lattice waveguide being able to guide the energy shifting, the energy distribution in section showing spreading and compression alternately in the x and y directions, and the changes in both directions are on the mutual influence, mutual constraints. When the waveguide has a little turning, the lattice array can guide the beam to change the transmission direction, the beam energy can be shifting completely along the lattice after over a certain distance transmission.